The Vietnamese government had made the call after Doan Thi Huong's co-accused, Indonesian woman Siti Aisyah, was released on Monday.

Vietnamese national Doan Thi Huong being eescorted by Malaysian police for a court appearance at the magistrates' court in Sepang on April 13, 2017, for her alleged role in the assassination of Kim Jong Nam, the half-brother of North Korean leader Kim Jong Un.

Manan Vatsyayana | AFP | Getty Images

Malaysia's attorney-general on Thursday rejected Vietnam's request to free a woman accused of the murder of Kim Jong Nam, the half-brother of North Korea's leader, and a court set April 1 for her trial to resume.

Huong and Siti Aisyah were charged with killing Kim Jong Nam by smearing his face with VX poison, a banned chemical weapon, at Kuala Lumpur airport in February 2017.

"It's our complaint that the public prosecution has not acted fairly and justly to Doan Thi Huong," her lawyer Hisyam Teh, who asked for an adjournment on the grounds that his client was unwell.

Teh told the court the rejection of Vietnam's request was "perverse", and a case of discrimination, as the attorney-general had favored one party over another, since the court had ordered both to enter their defense.

Vietnam's ministers of justice and foreign affairs are communicating with their Malaysian counterparts to secure his client's release, Teh added.

Prosecutors had sprung a surprise on Monday by asking the court to drop the charge against Siti Aisyah and free her. The Indonesian embassy flew her to Jakarta the same day.

The trial featured airport video recordings of two women allegedly assaulting Kim Jong Nam while he prepared to check in for a flight.

In one, a woman identified as Huong puts her hands on Kim's face, while a blurry image shows someone the prosecution identified as Siti Aisyah hurrying away.

Teh rejected speculation that Siti Aisyah's release was due to a lack of video evidence against her, saying the court had already established a case against both.

"So it makes no difference whatsover if Doan's image was caught on the CCTV camera, none at all," he said after the hearing.

Defence lawyers have maintained the women were pawns in an assassination orchestrated by North Korean agents. The North Korean embassy in Kuala Lumpur was defaced with graffiti just hours before the trial was to resume.

Interpol had issued a red notice for four North Koreans identified as suspects by Malaysian police who had left the country hours after the murder.

After the ruling, Huong was seen sobbing as she spoke with Vietnamese embassy officials, before being whisked away by police.